1. Field of the Invention
The present invention relates generally to transmission/reception of a signal in a communication system, and more particularly, to a method and an apparatus for supporting multi-band communication in a system band.
2. Description of the Related Art
A mobile communication system has been developed to enhance user activities and provide a voice service. This system has been gradually extended to support both data and voice services, and now provides a high-speed data service. Due to insufficient resources and user demands for a high-speed service, a more improved mobile communication technology is required in the current mobile communication system.
In order to meet such a demand, a standard for Long Term Evolution-Advanced (LTE-A) evolved from the 3rd Generation Partnership Project (3GPP) is being developed. The LTE-A will implement high-speed packet based communication having a maximum transmission rate of 1 Gbps. To this end, various plans have been discussed, such as for multiplexing a structure of a network and concurrently providing services in a particular area by a plurality of enhanced Node Bs (eNBs), and increasing the number of frequency bands supported by one eNB.
The technique for increasing the number of frequency bands includes a scheme for increasing bandwidths by allocating a plurality of different bands to one cell, and a scheme for supporting a plurality of small bands within one large band. The former is for communication devices supporting a relatively wide bandwidth and high data transmission rate, and the latter is for communication devices requiring a relatively narrow bandwidth and low data transmission rate.
An Orthogonal Frequency Division Multiplexing (OFDM) transmission mode transmits data by using the multi-carrier, and is a type of multi-carrier modulation mode for parallelizing symbol sequences input in series, modulating the symbol sequences to a plurality of subcarriers, that is, a plurality of subcarrier channels having an orthogonal relation, and then transmitting the plurality of subcarrier channels.
An LTE-A system has been designed to support different bands. Each band is considered as an independent cell, and one User Equipment (UE) is connected to a plurality of cells to perform communication. Meanwhile, an increase in costs occurs to process high-speed data. However, a voice-only device requiring a low-speed transmission rate or a device performing communication between machines such as a vending machine does not require a function supporting a multi-band or a technology using high power. A mobile communication system should be configured for continuous communication having a low transmission rate rather than a technology having a wider bandwidth and high efficiency, and should be highly efficient as to energy consumption and have a low-cost of implementation.
Furthermore, demands for a green technology with low power consumption and high efficiency are currently increased, and accordingly, a technology allowing various types of devices described above to coexist within a system is required.